Groups in the Periodic table Flashcards
(28 cards)
how many outer shell electrons do alkali metals have?
1 - so they all have similar chemical properties
what are the properties of alkali metals?
very soft - they can be cut with a knife
relatively low melting points
What kind of compounds do they form?
ionic compounds - they lose their single electron so easily
what do the alkali metals become (ions)?
1+ ion with a stable electronic structure
How do you tell how reactive an element is?
the more readily an electron is to lose its outer electron, the more reactive it is
what happens to the reactivity of the alkali metals as you go down?
they get more reactive -the outer election is more easily lost as it is further away from the nucleus so it is less strongly attracted meaning less energy is need to remove it
What is the equation when alkalis react with water?
sodium + water –sodium hydroxide + hydrogen
Lithium and water reaction
move around the surface and fizz furiously
sodium and potassium
will melt in the reaction, potassium gets hot enough to ignite the hydrogen gas being produced
How are the halogens bonded?
covalent bonding
what happens to the boring and melting points as you go down the halogens?
they increase
what substance is chlorine at room temp?
fairly reactive, poisonous, green gas
what substance is bromine at room temperature?
poisonous, red/brown liquid which gives off an orange vapour
what substance is iodine at room temp?
a dark grey crystalline solid which gives off a purple vapour when heated
what is the test for chlorine?
hold a piece of damp blue litmus paper over it, the chlorine will turn the litmus paper red and then bleach it white
what kind of ions do halogens create?
they gain an electron to become 1-
What does the reactivity do as you do down the group of halogens?
as you go down group 7, the halogens become less reactive - it gets harder to attract the extra electron to fill the outer shell when its further away from the nucleus
What do the Halogens react vigourously with?
metal halides
why are halogens at the top of the group more reactive?
the can attract the electron more easily
halogen reacting with hydrogen
chlorine + hydrogen – hydrogen chloride
what are hydrogen halides?
hydrogen and halides mixed together, they are soluble to form acidic solutions
what happens when a halogen reacts with another halogen salt solution?
its the halogen is more reactive than the solution, it displaces the solution
what happens when chlorine reacts with potassium bromide?
the chlorine will displace the bromine
the chlorine is reduced to chloride ions and the bromide ions is oxidised to form bromine
what substance is the noble gas at room temp?
colourless gas
